Residential Rooftop Research Articles

Adoption and spatial distribution disparities of residential plug-in and rooftop photovoltaic systems in Germany

In contrast to residential rooftop photovoltaic systems, plug-in photovoltaic systems offer a significantly lower barrier to entry in terms of upfront costs, installation complexity, and the need for roof space. These attributes make them appealing to a wider demographic and position them as transformative tools in the energy transition, opening opportunities for broader participation in renewable energy and aligning with the growing emphasis on energy justice and inclusivity. Nevertheless, adoption patterns for plug-in PV systems are not well understood, especially given their unique characteristics, which limit the applicability of insights derived from residential rooftop systems. This study addresses this research gap by applying spatial econometric models to investigate plug-in PV system adoption, revealing pronounced disparities. Our findings show that income support recipients are less negatively associated with plug-in PV adoption compared to larger rooftop systems, indicating that the lower upfront costs of plug-in PV systems may reduce financial barriers. Furthermore, the influence of household income on adoption is weaker for plug-in systems, suggesting that these systems may be more accessible to lower-income households. Contrary to expectations, solar radiation plays a less significant role in the adoption of plug-in PV. Additionally, the negative effect of the proportion of rented apartments on adoption is less pronounced for plug-in systems, highlighting their suitability for renters. Regional subsidies have demonstrated a positive impact on plug-in PV adoption, further emphasizing the potential of targeted support programs. Our findings can equip policymakers with the necessary insights to formulate strategies promoting the uptake of plug-in PV systems.

Two roof top farming concepts for residential buildings shifting towards sustainable communities: an exercise on the case of “Asmarat” with necessary re-adaptation of its architectural rooftop design

Desertification, deforestation, climate change, global warming, and economic instability are leading to serious problems in many countries. Two of these negative factors are the decrease in agriculture areas and food scarcity. This situation caused many countries to reconsider their agriculture polices and think of new solutions. The United Nations also addressed the problem via its “SDG—Sustainable Development Goals” agenda. One of its major goals is the change towards green and sustainable communities that can produce their own food. Rooftop farming in places with suitable climatic conditions was encouraged by the “SDG” and governments of many countries. The paper discusses the potential of utilizing Egyptian residential rooftops for rooftop farming, the Egyptian urban fabric is very dense with residential buildings. Taking the Egyptian “Asmarat” residential neighborhood as an exercise, the study aims to fulfilling the following three goals: 1- On a food security Level: if rooftop farming is extensively applied across all cities and villages in Egypt, a mass production threshold of exporting vegetables and fruits may be reached that will significantly participate in the overall national GDP, 2- On a socio-economic level: rooftop farming will create jobs for informal workers and the jobless, turning an individual from a jobless person to a busy one is the best practical solution for changing behavioral norms from the tendency towards crime, hanging around on the streets, and drug addiction towards a decent and productive society., and 3- On an environmental level.: Large cities suffer from crowds, high building densities, pollution, and scarcity of open green areas. Rooftop farming increases the “Urban Green Space—UGS” of the city, reduce pollution, decrease global warming, and purify the atmosphere.

A Three-Step Weather Data Approach in Solar Energy Prediction Using Machine Learning

Solar energy plays a critical part in lowering CO2 emissions and other greenhouse gases when integrated into the grid. Higher solar energy penetration is hindered by its intermittency leading to reliability issues. To forecast solar energy production, this study suggests a three-step forecasting method that selects weather variables with a moderate to strong positive correlation to solar radiation using Pearson correlation coefficient analysis. Low-level data fusion is used to combine weather inputs from a reliable local weather station and an on-site weather station, significantly improving the forecasting model’s accuracy regardless of the machine learning method used. Weather data was obtained from the Kisanhub Weather Station located in Cranfield University, UK and the meteorological station in Bedford, UK. In addition, PV power supply data was obtained from four solar plants. Using the Regression Learner app in MATLAB, the proposed architecture is tested on a utility scale solar plant (1 MW), showing a 6% and 13% prediction accuracy improvement when compared to solely using data from the on-site and local weather station respectively. It is further validated using data from three residential rooftop solar systems (8 kW, 10.5 kW and 15 kW), achieving root-mean square values of 0.0984, 0.0885, and 0.1425 respectively. The data was pre-processed using both rescaling and list-wise deletion methods. Training and testing data from the 1 MW solar plant was divided into 75% and 25% respectively, while 100% of the residential rooftop solar plants was used for validation.

Willingness to pay for solar adoption: Economic, ideological, motivational, and demographic factors

Residential solar energy installations are a critical component of the energy transition. Nonetheless, just a small fraction of all eligible households have installed solar panels. We investigate household willingness to pay (WTP) for a residential rooftop solar system using a stated preference approach and including socio-demographic, ideological, economic, and psychological factors.We implemented an online survey of 580 households in New York State who had not previously adopted a residential solar system. Respondents were presented with hypothetical PV systems with varying upfront costs and monthly savings that allow us to understand discount rates and payoff preferences. This allowed us to explore not only WTP and how it varies across the factors described above, but also how those factors affect discount rates and attitudes towards uncertain future payoffs from the systems. We limit our analysis to New York to control for variation in solar adoption policies from state to state, but these results are broadly generalizable to other US States and, with caveats, to advanced industrialized democracies.We find an average WTP of $7388.5 for installing a residential rooftop solar system. Respondents' WTP is $11.66 in upfront costs for each additional $1 of average monthly savings. We also find substantial heterogeneity in WTP and in trade-offs between upfront costs versus savings. Age, children in households, income, education, motivation, and ideology are all independent factors associated with WTP. We discuss a range of implications for policy and marketing to further increase rates of adoption in the future.

Exploring perceptions, cognitive factors, and motivations: A study on green structures on residential rooftops

Urban greenhouse and green roof cultivation propose a nature-based solution to current socio-ecological challenges in urban ecosystems, as it offers several socio-ecological solutions and benefits. The interdisciplinary techniques for scientific explorations of cognition and perception towards urban green structures could not get the attention of the researchers across varying scientific disciplines, especially in the developing world. Addressing the personal factors involved in human cognition and its subsequent impact on perceptions will lay the foundation for the studies of the field. The study included questions about socio-demographic characteristics and socio-environmental motivations, as well as a set of images depicting potential future of green structures. The study was accomplished in Tabriz city of Iran with 375 participants. The findings showed that individuals prioritize certain types of rooftop green structures based on their personal characteristics and motivations. Additionally, cognitive differences were observed among individuals based on age, gender, and marital status, leading to perceptual differences towards green structures. Socio-environmental motivations activate perceptual responses within individuals, influencing their preferences for specific types of rooftop greenhouses. Understanding the response of individuals towards green structure types is crucial for effective planning and design. This knowledge can enhance the overall success and satisfaction of rooftop green structures projects, leading to greater wellness and a positive impact on the environment.

Catchment-Scale Hydrologic Effectiveness of Residential Rain Gardens: A Case Study in Columbia, Maryland, USA

To mitigate the adverse impacts of urban stormwater on streams, watershed managers are increasingly using low-impact development and green infrastructure (LID-GI) stormwater control measures, such as rain gardens—vegetated depressional areas that collect and infiltrate runoff from rooftops and driveways. Their catchment-scale performance, however, can vary widely, and few studies have investigated the cumulative performance of residential rain gardens for event runoff control in intermediate-sized (i.e., 1–10 km2) suburban catchments. We modeled three years of continuous rainfall-runoff from a 3.1 km2 catchment in Columbia, MD, USA, using the Storm Water Management Model (SWMM). Various extents of rain garden implementation at residential houses were simulated (i.e., 25%, 50%, 75%, and 100% coverage) to determine the effects on peak flow, runoff volume, and lag time. On average, treating 100% of residential rooftops in the catchment reduced peak flows by 14.3%, reduced runoff volumes by 11.4%, and increased lag times by 3.2% for the 223 rainfall events during the simulation period. Peak flow reductions were greater for smaller storm events (p < 0.01). Our results show that residential rain gardens can significantly improve the runoff response of suburban catchments, and that they represent an effective and relatively low-cost option for urban watershed management and restoration.

Not All about the Money: The Role of Financial Information in Promoting Residential Rooftop Photovoltaics

This study investigates the role of financial information in shaping the intention to adopt (ITA) Residential Rooftop Photovoltaic (RPV) systems in Israel—a country with a surprisingly low RPV adoption rate given the high solar irradiance, and significant governmental support for RPV. We used an online survey of 899 respondents to examine how different presentations of RPV revenues impact both RPV deal comprehension and ITA. Our results align with existing literature on the roles of early technology adopters and pro-environmental characteristics while introducing two novel findings. First, households value their roofs—especially flat ones used for leisure. This negatively impacts ITA. Second, we found a positive correlation between trust in government entities and ITA, underscoring the importance of trust in institutions. Although financial information does enhance RPV deal comprehension, it does not significantly influence ITA. This study concludes that RPV penetration should not be promoted solely by financial incentives, but also by other motivations like environmental concerns, novelty seeking, and improved institutional trust.

Sustainable solar energy development in Zakho, Iraq: a techno-economic and environmental assessment

This study presents a solar energy roadmap aimed at attracting investors to capitalize on the abundant solar resources in Zakho, Iraq, for clean energy technology. The objective is to mitigate global warming effects caused by fossil fuel combustion and promote sustainable technological development. To end this, the study employs RETScreen Expert software to validate the techno-economic and environmental viability of a grid-connected solar photovoltaic system utilizing climatic data from the Astronaut Office Information System (NASA) Database. Additionally, the Photovoltaic Geographical Information System (PVGIS) modeling method determines optimal angles for installing residential rooftop Photovoltaic (PV) systems across selected locations. Results indicate that all selected locations are suitable for solar photovoltaic projects, with Rezgari identified as the optimal district due to its highest annual solar radiation of 1863.117 kWh/m2 and the highest annual electricity production at 7905.38 kWh. The capacity factor (CF) values fall within the range of 17.395-17.574%. The study reveals an annual greenhouse gas (GHG) emissions reduction ranging from 6.9876 to 7.1123 (tCO2) across four districts. Considering the financial and environmental indicators, Rooftop Photovoltaic Systems emerge as a sustainable and efficient solution to enhance the environment and prove economically viable in Zakho City.

Residential Rooftop Urban Agriculture: Architectural Design Recommendations

It is evident that, due to population growth, future urbanization and urban growth are inevitable. It is estimated that the food supply demand of future urban centers will grow, which will place an additional burden on the agriculture sector to produce more food. It is projected that securing the food supply chain for future urban centers will be a challenge. Urban agriculture can be regarded as a remedy for possible future challenges that the global food system will face. It might be able to reduce the future burden on the agriculture sector. This research proposes that urban rooftop agriculture, as a subset of urban agriculture, can produce local fresh food in dense urban environments. The principal aim of this research is to suggest a series of design recommendations for architects interested in designing residential buildings capable of rooftop food production. This research attempts to highlight the specific design recommendations and the principal limitations regarding designing residential rooftop farms. To extract the data for developing the proposed design recommendations and limitations, a review of the literature within the fields of urban agriculture, building-integrated agriculture, and horticulture was conducted. Based on the literature review results, this research suggests that the following three types of farming methods can be developed on residential rooftops: (1) open-air rooftop food production, (2) “low-tech” rooftop greenhouses, and (3) “high-tech” rooftop greenhouses. In addition, factors that can be considered principal limitations are suggested. In sum, this research proposes that current and future residential buildings can be designed so that their rooftops are utilized as farms. In this way, such buildings can contribute to delivering local fresh food to current and future metropolitan dwellers.

Ground-mounted or residential rooftop photovoltaic plant − European production or Chinese production: which is the most environmentally sustainable system? A case study in Italy

In recent years, decarbonization policies have pushed for a significant increase in renewable energies for power generation applications. European strategy aims to bring online over 320 GW of solar photovoltaics by 2025 and almost 600 GW by 2030. In this context, it is not only important to figure out the main hotspots of PV system but also to understand which are the best configurations from an environmental point of view. The analysis proposed in this paper aims to compare the environmental benefits of producing 1 kWh through two different system configurations: a ground-mounted PV plant (84 MW) and a residential rooftop PV plant (3 kW). In particular, the PERC (Passivated Emitter and Rear Cell) technology is investigated. In addition, in order to assess the influence of the energy mix used in the production of the PV components (mono-Si ingot, wafer, cell and module) on the LCA results, two different production sites are explored, i.e., in China and in Europe.

A Novel Distributed PV Data Virtual Collection With Continuous-Binary Denoising Auto-Encoders

The massive deployment of distributed photovoltaic (PV) installed on residential rooftops makes PV data collection and user privacy protection more prominent. To reduce number of devices and improve the ability to combat data loss in complex terrain environment, this paper proposes a deep learning-based virtual collection method. The proposed method employs a continuous-binary denoising auto-encoder (CB-DAE) to analyze the static characteristics of a multi-photovoltaic system (MPVS) and select reference PV (RPV). A data anomaly detector is constructed using ensemble learning to assist CB-DAE in data blind cleaning and decouple the dynamic characteristics from MPVS. To train the CB-DAE, a joint optimization model of data cleaning -RPV selection -the virtual collection is established, and the sparsity constraint of L1-norm is expressed as L0-norm constraint. Furthermore, an improved split Bregman using Lp-quasinorm approach is proposed to accelerate the solution. The proposed method is validated using data from Jan. 1 to Apr. 15, 2022, of 110 PVs from Badong County, Hubei Province, China. The impact of the scale of MPVS and the number of RPV on accuracy is also explored. Experimental results demonstrate the effectiveness and superiority of the proposed method.

Promoting residential rooftop solar photovoltaics in Indonesia: Net-metering or installation incentives?

The number of rooftop photovoltaic (PV) systems in Indonesia has increased massively following the implementation of the net-metering (NEM) scheme. However, it is still below the target due to high investment costs and low electricity prices. This study employs the System Advisory Model to conduct a techno-economic analysis to determine the viability of 2-kWp rooftop PV systems in Jakarta, Denpasar, and Kupang. The results show that the current levelized cost of energy (LCOE) exceeds the price of electricity. The net present value (NPV), payback period (PBP), and profitability index (PI) range from −975 to −424 USD, 10.3–12.5 years, and 0.72 to 0.88, respectively. These figures suggest that the existing NEM scheme is insufficient to render the rooftop PV system economically viable. However, sensitivity analysis results show that combining a 20 % installation incentive with a 40 % increase in NEM rates made rooftop PV systems more profitable in three cities. Furthermore, a location-based incentive scheme that considers varying solar irradiation levels can enhance the economic attractiveness of rooftop PV systems and foster widespread system adoption in Indonesia.

Climate Change Implications for Optimal Sizing of Residential Rooftop Solar Photovoltaic Systems in Qatar

Climate change poses critical challenges for Qatar’s energy-intensive residential building sector. This study evaluates the impact of projected climate warming on optimizing rooftop solar photovoltaics (PV) for villas. An integrated modelling approach is employed, combining building energy simulation, PV system optimization, and performance assessment under varying climate scenarios. A typical Qatari villa is modelled in DesignBuilder and simulated under the baseline (2002) conditions and the projected years 2016, 2050, and 2100, reflecting incremental warming. Results show the villa’s annual electricity consumption will grow 22% by 2100, with summer peaks escalating to 26% driven by surging cooling demands. Techno-economic optimization in HOMER Pro (version 3.10) verifies a grid-connected rooftop PV system as optimal in all years, with capacity expanding from 7.4 kW to 8.2 kW between 2002 and 2100 to meet rising air conditioning loads. However, as temperatures increase, PV’s energy contribution declines slightly from 18% to 16% due to climate change degrading solar yields. Nonetheless, the modelled PV system maintains strong financial viability, achieving 5–8 years of paybacks across scenarios. This analysis provides empirical evidence of distributed PV’s effectiveness for Qatar’s households amidst escalating cooling consumption. However, maintaining solar mitigation potential requires evolving PV sizing methodologies and incentives to account for declining panel productivity at the country’s peak temperatures exceeding 50 °C. Overall, this study’s integrated framework evaluates residential solar PV systems’ capabilities and appropriate policy evolution under projected climate impacts for the first time in Qatar. The modelling approach and conclusions can inform building codes and pro-solar policies to accelerate adoption for emissions reduction. With villas representing over 100,000 units in Qatar, widespread rooftop PV integration can meaningfully contribute to national sustainability targets if implementation barriers are addressed considering climate change effects.

Rooftop solar with net metering: An integrated investment appraisal

This paper develops a framework for a financial, economic, and stakeholder analysis of a residential rooftop solar net-metering program. The empirical focus of the paper is the net-metering program in Ontario, Canada, but the methodology is applicable to evaluating other public programs. The results highlight that without the Federal Government's subsidy for the initial investment cost, net-metered solar systems are not financially viable for representative households. Moreover, the stakeholder analysis reveals that for each additional net-metered system installed in Ontario, non-net-metered households experience financial losses of six times the benefits to the net-metered households. The net losses to the Federal Government of Canada and the Canadian economy are five and nine times the benefit to the net-metered households, respectively. The only stakeholder who benefits marginally is the Government of Ontario. In terms of environmental benefits, our estimate of the cost of greenhouse gas abatement by residential net-metered solar is 325 CAD per ton of CO2, which is significantly higher than the current (65 CAD in 2023) and future (170 CAD by 2030) national carbon price set by the Government of Canada.

Techno-economic analysis of residential rooftop photovoltaics in Spain

In response to the European Commission's renewable energy targets for 2030, this study presents a comprehensive, data-driven evaluation of the potential for electricity self-consumption in the Spanish residential sector based on rooftop PV systems. Utilizing real-time hourly electricity demand data and various surplus compensation policies, the research highlights the significance of data granularity, indicating that annual data-based PV estimations can lead to rooftop PV self-consumption capacity overestimations when compared to hourly data assessments. Furthermore, geographical variations reveal distinct rooftop PV self-consumption capacities between urban and rural areas, driven mainly by the prevalent building typologies. This discrepancy suggests that while rural regions, with their predominance of single-family dwellings, offer higher PV generation potential due to more available rooftop space, urban areas, dominated by multi-story buildings, face significant constraints in rooftop surface availability. Economically, the current surplus compensation policy in Spain reduces the profitability of PV installations, underscoring the necessity for enhanced policies to fully utilize all the available rooftop areas in the residential sector. The study's findings, particularly the revelation that residential rooftops in Spain may not be enough to meet the current electricity demand, emphasize the need for adaptive, region-specific policies and the potential role of energy communities. Policymakers and industry stakeholders are urged to prioritize rooftop utilization, ensuring the deployment of PV systems is both promoted and economically viable, steering Spain closer to its renewable energy and sustainability aspirations.

When the Sun Sets on Net Metering: How the Cancellation of Net Metering Impacted the Potential Adoption of Residential Rooftop Solar Photovoltaics in Regina, Saskatchewan

When the Sun Sets on Net Metering: How the Cancellation of Net Metering Impacted the Potential Adoption of Residential Rooftop Solar Photovoltaics in Regina, Saskatchewan

Analyzing the Impact of Ownership on the Patterns of Use in Residential Rooftops Case Study: New Cairo, Egypt

Analyzing the Impact of Ownership on the Patterns of Use in Residential Rooftops Case Study: New Cairo, Egypt

Peer effects on photovoltaics (PV) adoption and air quality spillovers in Poland

Peer effects played an important role in the diffusion of Poland's residential rooftop photovoltaic (PV) systems. I apply a panel econometric analysis to estimate the impact of peer effects. I lag the difference in time between a submitted PV installation request and installation completion, and control for endogenous group formation and correlated unobserved variables with a set of fixed effects. Additionally, I use a cohort model to analyse the variability in exposure to treatment, i.e. an installed base in a particular area, to observe the relationship between PV diffusion and air quality. First, peer effects were important for the diffusion of PV systems in Poland, as adding one installation in the previous month increases the probability of a new PV adoption in the same area by an average of 0.06 pp. Second, the supply of certified PV installers was not a constraint to the market development as their number increased with the expansion of PV systems. Finally, I demonstrate that areas with PV installations saw an average decrease of PM10 emissions by 0.01–0.09 μg per month. The study has relevant policy implications as peer effects (1) allow for the creation of local networks of stakeholders that would enhance the diffusion of clean energy sources and (2) create clusters of installations in well-developed regions, showing the need to intensify support efforts in underdeveloped areas.

Rainwater Harvesting as Sustainable Solution to Cope with Drinking Water Scarcity and Urban Flooding: A Case Study of Public Institutions in Lahore, Pakistan

Pakistan is currently facing physical and economic water scarcity issues, which have been further complicated by the rapid increase in its population and climate change. In affected areas, many methods are being used to tackle this problem, among which rainwater harvesting (RWH) provides the best alternative source of domestic water supply. In rainwater harvesting, a mechanism is designed to effectively collect surface runoff during rainfall events from residential rooftops. It has also been found that rainwater has great potential as a source of water supply in residential areas of major cities, such as Lahore, which is the focus of our study. This research paper examines rainwater harvesting as a sustainable solution to address the challenges of drinking water scarcity and urban flooding. The study discusses the benefits of rainwater harvesting, including reducing reliance on municipal water sources, improving water quality, and mitigating the impact of urban flooding. Additionally, the paper explores the use of filtered water points in conjunction with rainwater harvesting systems to provide clean drinking water to communities. The research draws on case studies from various regions to illustrate the effectiveness of rainwater harvesting as a sustainable solution to water scarcity and urban flooding. Ultimately, the study concludes that rainwater harvesting, when coupled with filtered water points, can offer an effective and sustainable solution to address drinking water scarcity and urban flooding.

Design of a Reverse Electrodialysis Plant for Salinity Gradient Energy Extraction in a Coastal Wastewater Treatment Plant.

The chemical potential difference at the discharge points of coastal Wastewater Treatment Plants (WWTPs) uncovers the opportunity to harness renewable salinity gradient energy (SGE). This work performs an upscaling assessment of reverse electrodialysis (RED) for SGE harvesting of two selected WWTPs located in Europe, quantified in terms of net present value (NPV). For that purpose, a design tool based on an optimization model formulated as a Generalized Disjunctive Program previously developed by the research group has been applied. The industrial scale-up of SGE-RED has already proven to be technically and economically feasible in the Ierapetra medium-sized plant (Greece), mainly due to a greater volumetric flow and a warmer temperature. At the current price of electricity in Greece and the up-to-date market cost of membranes of 10 EUR/m2, the NPV of an optimized RED plant in Ierapetra would amount to EUR117 thousand operating with 30 RUs in winter and EUR 157 thousand for 32 RUs in summer, harnessing 10.43 kW and 11.96 kW of SGE for the winter and summer seasons, respectively. However, in the Comillas facility (Spain), this could be cost-competitive with conventional alternatives, namely coal or nuclear power, under certain conditions such as lower capital expenses due to affordable membrane commercialization (4 EUR/m2). Bringing the membrane price down to 4 EUR/m2 would place the SGE-RED's Levelized Cost of Energy in the range of 83 EUR/MWh to 106 EUR/MWh, similar to renewable sources such as solar PV residential rooftops.